Dental matrix



May 5, 1936. F. M. HUTCHINSON DENTAL MATRIX Filed June l1, 1954 ZEw/ Patented May 5, 1936 UNITED STATES PATENT OFFICE '9 Claims.

This invention relates to a matrix for use in making dental fillings, particular those of the approximal type, and especially in cases where the filling consists of material such as composition or amalgam, which is soft and plastic when applied. The matrix itself consists of a piece of thin ductile sheet metal which is bound against the side of the tooth at which the filling is to be applied. My improvement is concerned with novel means for securing the matrix to the tooth, whereby, as compared with devices now in use, the application of the matrix is rendered more convenient, and it is fixed more securely in position. The invention consists in certain features and elements of construction in combination as herein shown and described, and as indicated by the claims.

In the drawing:

Figure 1 is a plan view of my improved matrix as it may be manufactured in multiple for sale to the individual dentist.

Figure 2 shows a single matrix with its fastening wire as cut from the multiple structure of Figure 1, and trimmed ready for use.

Figure 3 shows two adjacent teeth in side elevation with a matrix embodying my invention applied to one of them.

Figure 4 is a top plan View of the teeth and the matrix shown in Figure 3.

Figure 5 is a view similar to Figure 2, showing a slightly modified form of fastening means for the matrix.

Figure 6 is a side elevation of a tooth with a matrix applied thereto with the modified fastening means of Figure 5.

In Figure 1 I have illustrated a convenient form in which this matrix may be produced in multiple. The thin ductile metal is shown in the form of a strip, I, having small offset integral strap portions, 2 and 3, formed at regular intervals in its length in two rows, and having a length of wire, 4, threaded back and forth through these straps. This wire is to serve as the fastening means for the individual matrices which are made from the strap, I, by cutting it transversely, as at the dotted line, II. The wire is formed into short loops, 5, just beyond each of the strap portions 2, so that these loops extend beyond one edge of the strip, I, or in each separate matrix the loop, 5, projects slightly beyond one end of the matrix itself.

Beyond the opposite margin of the strip, I, the wire, 4, is bent upon itself at 6, these bends occurring at a considerable distance from the strip, I. When an individual matrix is cut off, as along line II, the wire is cut preferably at one side of the bend, 6, as indicated at I on Figure 1, thus forming two tie members, one of which terminates in a short hook, 8, and the other of which is left straight, as shown at 9. A corresponding 5 section of the strip, I, being severed as at II, forms the matrix It, as seen in Figure 2, and in accordance with the usual practice the corners, I2, and possibly other portions of the outline will be trimmed by the dentist to suit the particular 10 tooth on which the matrix is to be employed.

For illustrating the application of this matrix Figure 3 shows two adjacent teeth, A and B, the latter having the cavity to be treated facing the tooth, A. The matrix, I0, is inserted between the two teeth, either by entering it between them from above, or by first passing the ends, 8 and 9, of the wire ligature between the teeth, A and B, adjacent the gum line, and then shifting the matrix, I0, endwise into position. The wire, 8, is then brought around the tooth, B, passing it between that tooth and the next adjacent tooth (not shown) so that the portion, 8 of this wire will bear against the tooth, B, at the side opposite the matrix. In threading this wire between the teeth it may be found that the space is so small, or so filled up with gum tissue, that it is diflicult to pass the wire endwise through it. In such cases a doubled piece of dental floss is snapped into the space by forcing it between the teeth from above, and the loop of the floss is engaged with the hook-shaped end, 8, of the wire, which may then be drawn through the space which the dental floss has provided by forcing aside a little of the gum tissue.

Next, the free end of the wire, 8, is passed through the loop, 5, while the other wire, 9, is brought upwardly from the opposite end of the matrix and thence across the top of the tooth at 9 its free end being drawn down into engagement with the end of the wire, 8. When these ends are twisted together, as seen at I3, the wire passing around the tooth at 8 and the wire passing across the top of the tooth at 9 are tightened simultaneously, forming a ligature which draws the matrix snugly into position.

Like that shown in Figure 3, every tooth narrows somewhat toward the gum line, and unless some means is provided for engaging the top of the tooth, there is a tendency for the matrix to slip downwardly after the binding means has been once tightened. This loosens the hold of the. binding means and destroys the security of the matrix, thus making it impossible for the dentist to make a neat filling. But with the wire, 9,

passing across the top of the tooth and tightened simultaneously with the wire, 8 any tendency of the matrix to move downwardly is prevented, and it is therefore held securely in correct position as long as it is needed.

Another method of applying the matrix is as follows: After passing the hooked wire, 8, between the teeth, the small loop, 5, is caught with a special hooked instrument resembling a small button hook. The hooked wire, 8, is then drawn through the button hook, and by means of this instrument the loop and the hooked wire .are twisted together. When the wire, 8, has thus been made tight around the tooth, the wire, 9, is drawn across the top of the tooth and into the button hook instrument along with the end portion of the wire, 8, and these two are then twisted together to tighten the wire, 9.

Figure 5 illustrates a slight modification of my invention in which a matrix, 20, which may be generally similar to the matrix, I0, is provided with two entirely separate binding wires, IB and I9; the former may have a hooked end, 2|, corresponding to the hook, 8, of Figure 2. These wires are secured to the matrix by being threaded under the offset strap portions, 22 and 23. When the matrix is applied to the tooth, such as that shown at C in Figure 6, the wire, I9, is led upwardly at both ends of the matrix, so that a portion of the wire passes across the top of the tooth, and the two ends of it are twisted together, as seen at NV. The other wire, I8, is passed around the tooth, and its two ends are twisted together, as seen at I8 and independently of the wire, IS. The ultimate result is similar to that secured by the construction already described, except that there are two fastenings to be made instead of one. The matrix is bound firmly to the tooth by the wire, I8, and is prevented from moving downwardly by the engagement of the wire, I9, with the top of the tooth.

The wire ligatures which are a feature of this invention are far superior to ligatures of thread or dental floss, which are frequently used but which are quite likely to break, either at the time they are tied in place, or after work has been started on the tooth. And the provision of the offset strap portions, 2 and 3, or 22 and 23, permits these binding wires to lie wholly outside the matrix,that is, against its outer surface,-so that no portion of the wires passes between the matrix and the tooth surface. It may be understood that the hooked formation shown at 8 in Figure 1, and at 2I in Figure 5, is optional, but that this feature will frequently be found of convenience in getting the wire inserted between the teeth, as already described. When the matrices are furnished in strip form, as shown in Figure 1, the line II at which they are severed will be positioned according to the location of the tooth on which the matrix is to be used. That is, the particular matrix shown in Figure 2 would be suitable for use with distal cavities on the lower teeth and mesial cavities on the uppers, on the right side of the mouth, and for mesial cavities on the lower teeth and distal cavities on the uppers on the left side of the mouth. For mesial cavities on the lower and distal cavities on the upper teeth on the right side of the mouth, or for distal cavities on the lowers and mesial cavities on the uppers at the left side of the mouth, the matrix may be cut from the opposite end of the strip, I, with the line of severance nearer the left side of the wires, 8 and 9, so

that the small loop, 5, will come at the left end instead of at the right, as seen in Figure 2.

Thus it will be seen that I have produced a dental matrix which may be conveniently and economically manufactured and handled in multiple, and which may be readily adapted to practically any situation in the dentists practice in which he would employ a device of this character; and, finally, that the arrangement of the ligature provided by my invention permits of convenient application .and ensures a secure fastening which will not be loosened by the various strains incident to the work which is performed with the matrix in place.

While there is shown and described herein certain specific structure embodying the invention, it will be manifest to those skilled in the art that various modifications and re-arrangements of the parts may be made without departing from the spirit and scope of the invention, and that the same is not limited to the particular form herein shown and described, except in so far as indicat ed by the appended claims.

I claim:

1. A matrix of thin sheet material adapted to be applied laterally against the tooth and a ligature of two strands engaged with the matrix adjacent its opposite ends for securing it to a tooth, one strand adapted to be extended around the tooth for binding the matrix against it and the other strand adapted to be extended upwardly from said engagements adjacent the opposite ends of the matrix and thence across the top of the tooth in contact therewith.

2. A matrix of thin sheet material and a ligature comprising two strands of wire, the matrix having straps passing transversely over said strands to position them against the outer surface of the matrix, one of said strands adapted to be extended around the tooth for binding the matrix thereon and the other strand arranged to be extended upwardly from the confining straps adjacent each end of the matrix and thence across the top of the tooth in contact therewith, the ends of each strand being adapted to be twisted together for tightening the wire and securing the matrix firmly in position.

3. A matrix of thin sheet material, and a ligature for securing it to a tooth, said matrix being through said offset straps and against the outer surface of the matrix over the interval between the positions of said offset straps and adapted to be extended around the tooth and to have its opposite ends secured together outside the interval between the positions of said offset straps.

l. A matrix of thin sheet material and means for securing it to a tooth comprising a wire ligature consisting of a single piece of wire formed with a short loop projecting from one end of the matrix, and with free ends extending from the opposite end of the matrix, one free end formed and arranged for passing around the tooth and thence through the loop and upwardly, and the other end formed and arranged for passing over the top of the tooth and joined with the upwardly trending end.

5. A matrix of thin sheet material and means for securing it to a tooth comprising a ligature having two strands extending against the outer surface of the matrix and joined in a short loop projecting from one end of said matrix, said strands being held together adjacent the opposite end of the matrix and then dividing so that one of said strands is adapted to be extended around the tooth and thence upwardly through the short loop for connection with the other strand, with one of said strands bearing against the top of the tooth.

6. In the combination defined in claim 5, said ligature consisting of a wire the ends of which may be twisted together to connect them, whereby further twisting of the ends will tighten the ligature around the tooth and across the top of the same.

7. In the combination defined in claim 5, said matrix being provided with straps passing transversely over the two strands of the ligature ad- I jacent each end of the matrix for securing the short loops which project beyond one margin of the strip at intervals corresponding to the intervals between the straps, and longer loops projecting from the opposite margin of the strip so that the strip may be cut into lengths each containing one of the straps at each margin, and the ligature may be cut adjacent the outer end of each of the longer loops to form a plurality of matrices with binding means secured to each of them.

9. A matrix of thin sheet material adapted to be applied laterally against a tooth, and binding means for securing it thereto comprising a portion extending laterally against the outer face of the matrix from end to end thereof with a portion adapted to extend beyond the ends of the matrix and around the tooth for binding the matrix against it, and another portion adapted to extend upwardly from points adjacent the opposite ends of the matrix and thence across the top of the tooth in contact therewith, together with means on the matrix slidably engaging said binding means to position it while permitting said binding means to shift endwise over the matrix but not upwardly or downwardly thereon.

FLOYD M. HUTCHINSON. 

